Referring to Chinese Patent publication No. 104821419, which discloses a battery pack thermal management device of an electric vehicle, the device includes a fan, an evaporator, a battery module and heat preserving cotton. A silica gel heating film is provided between the battery module and a cooling plate. The cooling plate adopts a structure of plate machine plus flow passage. The evaporator and the cooling plate are connected and used in series, the cold air of the evaporator certainly needs an air pipeline or an air passage so as to be sent into the battery box, thereby implementing that the outer cold air enters into the box to cool the battery. When heating, the temperature of the large amount of cold air in the battery box and the air pipeline rises after being heated, and then forms hot gas, which will flow inside the battery box, and forms condensate water when meeting solid wall surfaces with low temperature. Referring to Chinese Patent publication No. 103326085, which discloses a Li-ion power battery pack, including a battery box, an inlet pipe, a top cover plate, a single battery, an outlet pipe and a liquid cooling pipe. A battery box heat preserving layer is adhered on the inner wall of the battery box. A module heat preserving layer is adhered at the surface of the battery module. Phase-change material is filled between the cooling pipe and the single battery.
At present, the Li-ion battery performs best charge-discharge performance and longest service life when the temperature is within the range of 20-40 degrees. However, generally in the market, the thermal management system is adopted to keep the battery pack working in the best working range, so as to provide best driving experience to customers. The manner of the thermal management system includes solutions of initiative air cooling and air heating, and liquid cooling and liquid heating etc. If the evaporator of initiative air cooling or the water cooling plate of liquid cooling is arranged in the airtight interior of the battery box, phenomenon of high-temperature moisture condensation will occur on the surface of the evaporator and the surface of the cooling plate. In low-temperature environment, when the hot air sent by the air heating manner and the hot air heated by hot water meets the cold condensate water, which has the risk of permeating into the electronic management system, results in failure of the electron devices, for example, short circuit may be caused by the condensate water of the hot gas in the cell supervision circuit (CSC) in the battery box, causing breakdown of the whole battery management system, which leads to operation malfunction of the vehicle.
Therefore, it is needed to provide a new battery pack, so as to overcome the above defects.